Field of the Invention
The present invention relates to a cosmetic composition containing an N-medium-chain-acyl basic amino acid powder, an inorganic powder and an oil material.
Discussion of the Background
N-long-chain-acyl basic amino acid having an acyl group having 11 or more carbon atoms has a particular plate-like crystal structure, which affords good slipperiness, and is used as a powder material for cosmetics. The N-long-chain-acyl basic amino acid powder further has an effect of suppressing gloss and stickiness of cosmetics, which are derived from an oily material therein (patent document 1). In addition, there is a known technique for suppressing a hard feeling during use and a drying feeling, which are characteristic of inorganic powders, and affording a soft feeling of touch and high moisturizing feeling, by using N-long-chain-acyl basic amino acid as a surface treating agent for inorganic powders (patent document 2).
However, as stated in patent document 2, N-long-chain-acyl basic amino acid that exists separately without adhering to a surface of inorganic powder impairs the slipperiness, smoothness and spreadability of a cosmetic obtained using inorganic powder and N-long-chain-acyl basic amino acid, and sometimes also impairs translucency and luminous finish of the skin after application, since the cosmetic fails to form a uniform coated film. This problem becomes more remarkable when an N-long-chain-acyl basic amino acid powder and an oily material are combined. Furthermore, when a solid cosmetic is produced by pressing a composition containing an N-long-chain-acyl basic amino acid powder, the solid cosmetic sometimes becomes too hard. In this case, problems occur in that the “pick up” of the solid cosmetic to a sponge and the like that rub the surface of a solid cosmetic becomes poor, and a phenomenon of “glossy surface” occurs on the surface of a solid cosmetic by continuously rubbing the surface with a sponge and the like. The Examples of the aforementioned patent documents 1 and 2 do not describe a cosmetic containing N-medium-chain-acyl basic amino acid having a medium-chain acyl group having 6-10 carbon atoms.
Also, patent document 3 describes a skin and hair cosmetic composition containing N-long-chain-acyl basic amino acid, and patent document 4 describes a hair cosmetic composition containing N-long-chain-acyl basic amino acid. However, the Examples of patent documents 3 and 4 do not describe a cosmetic containing an N-medium-chain-acyl basic amino acid powder, an inorganic powder and an oil agent.